A deeper look at the frequency data (our own, and also from some others) reveals a number of other interesting things about what happened on Tuesday 25th May 2021 in Queensland.
AEMO also published something else today which (whilst not as publicised as the ESOO) will be of keen interest to many stakeholders in South Australia…
Our guest author Stephen Sproul looks at how the Dalrymple Battery Energy Storage System (BESS), currently the only source of virtual inertia on the NEM, responded to the November 2019 SA islanding event.
Another islanding event separated the SA region from the rest of the NEM yesterday (Monday, 2nd of March). Allan O’Neil investigates what happened before the event and possible causes.
As time has permitted, I’ve invested some time to prepare this first stage of a review of what went on during the period from 31st Jan 2020 to 17th Feb 2020 – a period during which the South Australian region formed its own frequency island following the transmission line damage. A period we’ve called an ‘accelerated accidental experiment’.
Two weeks ago (Monday 17th February) a ‘temporary fix’ was put in place to reconnect SA with VIC following the transmission line outage that began on 31st January 2020. Well, we’ve islanded again today….
Guest author, Allan O’Neil, takes a look at what’s happened in the (islanded) market for FCAS services in South Australia over the past two weeks with Heywood out of service. He notes:
“generators in SA as a group would have paid out roughly twice in contingency raise FCAS costs what they earned from selling energy”
Guest author, Allan O’Neil delves further into understanding what happened in response to the transmission tower failures on 31st January 2020 that sent system frequency in South Australia and led to a large reversal of flows.
Cautioning readers that I am a novice at reading frequency data in this manner, I take a first look at how the frequency in Melbourne and South Australia varied at the time of the transmission outage at 13:24:30 on Friday 31st January 2020.
In order to help us (internally) map out all the different threads to explore in terms of what happened on Friday 31st January 2020 on a remarkable day in the NEM, I’ve identified a few of the key threads here over the weekend. More articles to follow as time permits….
Today (Fri 31 January 2020) saw NEM-wide demand reach levels never seen before (excepting 29th January 2009). This was just the start of the white knuckle ride.
A first (and perhaps only – as this took longer than initially planned) walk through some of the interesting points of what happened yesterday (Sat 16th Nov 2019) when South Australia islanded from the rest of the NEM with the trip of the Heywood interconnector.
The multi-region islanding event on Saturday 25th August was a very rare event – perhaps the only one’s that occurred in the history of the NEM. It has generated plenty of questions – and driven our analysis further. We share some more observations here, and keenly await the draft AEMO report.
Following on from Saturday’s islanding event, we use our current interest in AEMO’s 4-second SCADA data to prove a little more…
Both the QNI and the Heywood interconnectors tripped around the same time on Saturday 25th August 2018 (not apparent at this time which one was first, and why), leading to both QLD and SA regions being separately islanded from the rest of the mainland NEM. This also contributed to over 1,000MW of load shedding in NSW and VIC, and presumably some frequency excursions in QLD and SA.